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  2. North American X-15 - Wikipedia

    en.wikipedia.org/wiki/North_American_X-15

    The X-15's highest speed, 4,520 miles per hour (7,274 km/h; 2,021 m/s), [1] was achieved on 3 October 1967, [2] when William J. Knight flew at Mach 6.7 at an altitude of 102,100 feet (31,120 m), or 19.34 miles. This set the official world record for the highest speed ever recorded by a crewed, powered aircraft, which remains unbroken. [3] [4]

  3. Hypersonic flight - Wikipedia

    en.wikipedia.org/wiki/Hypersonic_flight

    Hypersonic flight is flight through the atmosphere below altitudes of about 90 km (56 mi) at speeds greater than Mach 5, a speed where dissociation of air begins to become significant and high heat loads exist. Speeds over Mach 25 have been achieved below the thermosphere as of 2020. [citation needed] Reentry vehicle (RV) after an 8,000 ...

  4. Hypersonic speed - Wikipedia

    en.wikipedia.org/wiki/Hypersonic_speed

    Hypersonic speed. "Hypersonic" redirects here. For other uses, see Hypersonic (disambiguation). In aerodynamics, a hypersonic speed is one that exceeds five times the speed of sound, often stated as starting at speeds of Mach 5 and above. [1] The precise Mach number at which a craft can be said to be flying at hypersonic speed varies, since ...

  5. Speed of sound - Wikipedia

    en.wikipedia.org/wiki/Speed_of_sound

    e. The speed of sound is the distance travelled per unit of time by a sound wave as it propagates through an elastic medium. More simply, the speed of sound is how fast vibrations travel. At 20 °C (68 °F), the speed of sound in air is about 343 m/s (1,125 ft/s; 1,235 km/h; 767 mph; 667 kn), or 1 km in 2.91 s or one mile in 4.69 s.

  6. Mach number - Wikipedia

    en.wikipedia.org/wiki/Mach_number

    The Mach number (M or Ma), often only Mach, (/ mɑːk /; German: [max]) is a dimensionless quantity in fluid dynamics representing the ratio of flow velocity past a boundary to the local speed of sound. [1][2] It is named after the Austrian physicist and philosopher Ernst Mach. where: M is the local Mach number, u is the local flow velocity ...

  7. Loaded march - Wikipedia

    en.wikipedia.org/wiki/Loaded_march

    To complete training and as part of an annual test of their fitness, legionnaires must complete the 8 kilometres TAP ("Paratroopers 8 kilometer") of 8 kilometers (5 mi) loaded with rifle, helmet and a 12 kilograms (26 lb) pack in under 40 minutes, and a night march of 25 kilometers (16 mi) in three hours with a load of 18 kilograms (40 lb ...

  8. Airspeed - Wikipedia

    en.wikipedia.org/wiki/Airspeed

    Airspeed is commonly given in knots (kn). Since 2010, the International Civil Aviation Organization (ICAO) recommends using kilometers per hour (km/h) for airspeed (and meters per second for wind speed on runways), but allows using the de facto standard of knots, and has no set date on when to stop.

  9. Speed of light - Wikipedia

    en.wikipedia.org/wiki/Speed_of_Light

    The speed of light in vacuum, commonly denoted c, is a universal physical constant that is exactly equal to 299,792,458 metres per second (approximately 300,000 kilometres per second; 186,000 miles per second; 671 million miles per hour).